Commit | Line | Data |
---|---|---|
a4ffc152 MP |
1 | /* |
2 | * Copyright (C) 2012 Red Hat, Inc. | |
3 | * | |
4 | * Author: Mikulas Patocka <mpatocka@redhat.com> | |
5 | * | |
6 | * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors | |
7 | * | |
8 | * This file is released under the GPLv2. | |
9 | * | |
10 | * In the file "/sys/module/dm_verity/parameters/prefetch_cluster" you can set | |
11 | * default prefetch value. Data are read in "prefetch_cluster" chunks from the | |
12 | * hash device. Setting this greatly improves performance when data and hash | |
13 | * are on the same disk on different partitions on devices with poor random | |
14 | * access behavior. | |
15 | */ | |
16 | ||
17 | #include "dm-bufio.h" | |
18 | ||
19 | #include <linux/module.h> | |
20 | #include <linux/device-mapper.h> | |
65ff5b7d | 21 | #include <linux/reboot.h> |
a4ffc152 MP |
22 | #include <crypto/hash.h> |
23 | ||
24 | #define DM_MSG_PREFIX "verity" | |
25 | ||
65ff5b7d ST |
26 | #define DM_VERITY_ENV_LENGTH 42 |
27 | #define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR" | |
28 | ||
a4ffc152 MP |
29 | #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144 |
30 | ||
31 | #define DM_VERITY_MAX_LEVELS 63 | |
65ff5b7d ST |
32 | #define DM_VERITY_MAX_CORRUPTED_ERRS 100 |
33 | ||
34 | #define DM_VERITY_OPT_LOGGING "ignore_corruption" | |
35 | #define DM_VERITY_OPT_RESTART "restart_on_corruption" | |
a4ffc152 MP |
36 | |
37 | static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE; | |
38 | ||
39 | module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR); | |
40 | ||
65ff5b7d ST |
41 | enum verity_mode { |
42 | DM_VERITY_MODE_EIO, | |
43 | DM_VERITY_MODE_LOGGING, | |
44 | DM_VERITY_MODE_RESTART | |
45 | }; | |
46 | ||
47 | enum verity_block_type { | |
48 | DM_VERITY_BLOCK_TYPE_DATA, | |
49 | DM_VERITY_BLOCK_TYPE_METADATA | |
50 | }; | |
51 | ||
a4ffc152 MP |
52 | struct dm_verity { |
53 | struct dm_dev *data_dev; | |
54 | struct dm_dev *hash_dev; | |
55 | struct dm_target *ti; | |
56 | struct dm_bufio_client *bufio; | |
57 | char *alg_name; | |
58 | struct crypto_shash *tfm; | |
59 | u8 *root_digest; /* digest of the root block */ | |
60 | u8 *salt; /* salt: its size is salt_size */ | |
61 | unsigned salt_size; | |
62 | sector_t data_start; /* data offset in 512-byte sectors */ | |
63 | sector_t hash_start; /* hash start in blocks */ | |
64 | sector_t data_blocks; /* the number of data blocks */ | |
65 | sector_t hash_blocks; /* the number of hash blocks */ | |
66 | unsigned char data_dev_block_bits; /* log2(data blocksize) */ | |
67 | unsigned char hash_dev_block_bits; /* log2(hash blocksize) */ | |
68 | unsigned char hash_per_block_bits; /* log2(hashes in hash block) */ | |
69 | unsigned char levels; /* the number of tree levels */ | |
70 | unsigned char version; | |
71 | unsigned digest_size; /* digest size for the current hash algorithm */ | |
72 | unsigned shash_descsize;/* the size of temporary space for crypto */ | |
73 | int hash_failed; /* set to 1 if hash of any block failed */ | |
65ff5b7d ST |
74 | enum verity_mode mode; /* mode for handling verification errors */ |
75 | unsigned corrupted_errs;/* Number of errors for corrupted blocks */ | |
a4ffc152 | 76 | |
a4ffc152 MP |
77 | struct workqueue_struct *verify_wq; |
78 | ||
79 | /* starting blocks for each tree level. 0 is the lowest level. */ | |
80 | sector_t hash_level_block[DM_VERITY_MAX_LEVELS]; | |
81 | }; | |
82 | ||
83 | struct dm_verity_io { | |
84 | struct dm_verity *v; | |
a4ffc152 MP |
85 | |
86 | /* original values of bio->bi_end_io and bio->bi_private */ | |
87 | bio_end_io_t *orig_bi_end_io; | |
88 | void *orig_bi_private; | |
89 | ||
90 | sector_t block; | |
91 | unsigned n_blocks; | |
92 | ||
003b5c57 | 93 | struct bvec_iter iter; |
a4ffc152 MP |
94 | |
95 | struct work_struct work; | |
96 | ||
a4ffc152 MP |
97 | /* |
98 | * Three variably-size fields follow this struct: | |
99 | * | |
100 | * u8 hash_desc[v->shash_descsize]; | |
101 | * u8 real_digest[v->digest_size]; | |
102 | * u8 want_digest[v->digest_size]; | |
103 | * | |
104 | * To access them use: io_hash_desc(), io_real_digest() and io_want_digest(). | |
105 | */ | |
106 | }; | |
107 | ||
3b6b7813 MP |
108 | struct dm_verity_prefetch_work { |
109 | struct work_struct work; | |
110 | struct dm_verity *v; | |
111 | sector_t block; | |
112 | unsigned n_blocks; | |
113 | }; | |
114 | ||
a4ffc152 MP |
115 | static struct shash_desc *io_hash_desc(struct dm_verity *v, struct dm_verity_io *io) |
116 | { | |
117 | return (struct shash_desc *)(io + 1); | |
118 | } | |
119 | ||
120 | static u8 *io_real_digest(struct dm_verity *v, struct dm_verity_io *io) | |
121 | { | |
122 | return (u8 *)(io + 1) + v->shash_descsize; | |
123 | } | |
124 | ||
125 | static u8 *io_want_digest(struct dm_verity *v, struct dm_verity_io *io) | |
126 | { | |
127 | return (u8 *)(io + 1) + v->shash_descsize + v->digest_size; | |
128 | } | |
129 | ||
130 | /* | |
131 | * Auxiliary structure appended to each dm-bufio buffer. If the value | |
132 | * hash_verified is nonzero, hash of the block has been verified. | |
133 | * | |
134 | * The variable hash_verified is set to 0 when allocating the buffer, then | |
135 | * it can be changed to 1 and it is never reset to 0 again. | |
136 | * | |
137 | * There is no lock around this value, a race condition can at worst cause | |
138 | * that multiple processes verify the hash of the same buffer simultaneously | |
139 | * and write 1 to hash_verified simultaneously. | |
140 | * This condition is harmless, so we don't need locking. | |
141 | */ | |
142 | struct buffer_aux { | |
143 | int hash_verified; | |
144 | }; | |
145 | ||
146 | /* | |
147 | * Initialize struct buffer_aux for a freshly created buffer. | |
148 | */ | |
149 | static void dm_bufio_alloc_callback(struct dm_buffer *buf) | |
150 | { | |
151 | struct buffer_aux *aux = dm_bufio_get_aux_data(buf); | |
152 | ||
153 | aux->hash_verified = 0; | |
154 | } | |
155 | ||
156 | /* | |
157 | * Translate input sector number to the sector number on the target device. | |
158 | */ | |
159 | static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector) | |
160 | { | |
161 | return v->data_start + dm_target_offset(v->ti, bi_sector); | |
162 | } | |
163 | ||
164 | /* | |
165 | * Return hash position of a specified block at a specified tree level | |
166 | * (0 is the lowest level). | |
167 | * The lowest "hash_per_block_bits"-bits of the result denote hash position | |
168 | * inside a hash block. The remaining bits denote location of the hash block. | |
169 | */ | |
170 | static sector_t verity_position_at_level(struct dm_verity *v, sector_t block, | |
171 | int level) | |
172 | { | |
173 | return block >> (level * v->hash_per_block_bits); | |
174 | } | |
175 | ||
176 | static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level, | |
177 | sector_t *hash_block, unsigned *offset) | |
178 | { | |
179 | sector_t position = verity_position_at_level(v, block, level); | |
180 | unsigned idx; | |
181 | ||
182 | *hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits); | |
183 | ||
184 | if (!offset) | |
185 | return; | |
186 | ||
187 | idx = position & ((1 << v->hash_per_block_bits) - 1); | |
188 | if (!v->version) | |
189 | *offset = idx * v->digest_size; | |
190 | else | |
191 | *offset = idx << (v->hash_dev_block_bits - v->hash_per_block_bits); | |
192 | } | |
193 | ||
65ff5b7d ST |
194 | /* |
195 | * Handle verification errors. | |
196 | */ | |
197 | static int verity_handle_err(struct dm_verity *v, enum verity_block_type type, | |
198 | unsigned long long block) | |
199 | { | |
200 | char verity_env[DM_VERITY_ENV_LENGTH]; | |
201 | char *envp[] = { verity_env, NULL }; | |
202 | const char *type_str = ""; | |
203 | struct mapped_device *md = dm_table_get_md(v->ti->table); | |
204 | ||
205 | /* Corruption should be visible in device status in all modes */ | |
206 | v->hash_failed = 1; | |
207 | ||
208 | if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS) | |
209 | goto out; | |
210 | ||
211 | v->corrupted_errs++; | |
212 | ||
213 | switch (type) { | |
214 | case DM_VERITY_BLOCK_TYPE_DATA: | |
215 | type_str = "data"; | |
216 | break; | |
217 | case DM_VERITY_BLOCK_TYPE_METADATA: | |
218 | type_str = "metadata"; | |
219 | break; | |
220 | default: | |
221 | BUG(); | |
222 | } | |
223 | ||
224 | DMERR("%s: %s block %llu is corrupted", v->data_dev->name, type_str, | |
225 | block); | |
226 | ||
227 | if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS) | |
228 | DMERR("%s: reached maximum errors", v->data_dev->name); | |
229 | ||
230 | snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu", | |
231 | DM_VERITY_ENV_VAR_NAME, type, block); | |
232 | ||
233 | kobject_uevent_env(&disk_to_dev(dm_disk(md))->kobj, KOBJ_CHANGE, envp); | |
234 | ||
235 | out: | |
236 | if (v->mode == DM_VERITY_MODE_LOGGING) | |
237 | return 0; | |
238 | ||
239 | if (v->mode == DM_VERITY_MODE_RESTART) | |
240 | kernel_restart("dm-verity device corrupted"); | |
241 | ||
242 | return 1; | |
243 | } | |
244 | ||
a4ffc152 MP |
245 | /* |
246 | * Verify hash of a metadata block pertaining to the specified data block | |
247 | * ("block" argument) at a specified level ("level" argument). | |
248 | * | |
249 | * On successful return, io_want_digest(v, io) contains the hash value for | |
250 | * a lower tree level or for the data block (if we're at the lowest leve). | |
251 | * | |
252 | * If "skip_unverified" is true, unverified buffer is skipped and 1 is returned. | |
253 | * If "skip_unverified" is false, unverified buffer is hashed and verified | |
254 | * against current value of io_want_digest(v, io). | |
255 | */ | |
256 | static int verity_verify_level(struct dm_verity_io *io, sector_t block, | |
257 | int level, bool skip_unverified) | |
258 | { | |
259 | struct dm_verity *v = io->v; | |
260 | struct dm_buffer *buf; | |
261 | struct buffer_aux *aux; | |
262 | u8 *data; | |
263 | int r; | |
264 | sector_t hash_block; | |
265 | unsigned offset; | |
266 | ||
267 | verity_hash_at_level(v, block, level, &hash_block, &offset); | |
268 | ||
269 | data = dm_bufio_read(v->bufio, hash_block, &buf); | |
fc0a4461 | 270 | if (IS_ERR(data)) |
a4ffc152 MP |
271 | return PTR_ERR(data); |
272 | ||
273 | aux = dm_bufio_get_aux_data(buf); | |
274 | ||
275 | if (!aux->hash_verified) { | |
276 | struct shash_desc *desc; | |
277 | u8 *result; | |
278 | ||
279 | if (skip_unverified) { | |
280 | r = 1; | |
281 | goto release_ret_r; | |
282 | } | |
283 | ||
284 | desc = io_hash_desc(v, io); | |
285 | desc->tfm = v->tfm; | |
286 | desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; | |
287 | r = crypto_shash_init(desc); | |
288 | if (r < 0) { | |
289 | DMERR("crypto_shash_init failed: %d", r); | |
290 | goto release_ret_r; | |
291 | } | |
292 | ||
293 | if (likely(v->version >= 1)) { | |
294 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
295 | if (r < 0) { | |
296 | DMERR("crypto_shash_update failed: %d", r); | |
297 | goto release_ret_r; | |
298 | } | |
299 | } | |
300 | ||
301 | r = crypto_shash_update(desc, data, 1 << v->hash_dev_block_bits); | |
302 | if (r < 0) { | |
303 | DMERR("crypto_shash_update failed: %d", r); | |
304 | goto release_ret_r; | |
305 | } | |
306 | ||
307 | if (!v->version) { | |
308 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
309 | if (r < 0) { | |
310 | DMERR("crypto_shash_update failed: %d", r); | |
311 | goto release_ret_r; | |
312 | } | |
313 | } | |
314 | ||
315 | result = io_real_digest(v, io); | |
316 | r = crypto_shash_final(desc, result); | |
317 | if (r < 0) { | |
318 | DMERR("crypto_shash_final failed: %d", r); | |
319 | goto release_ret_r; | |
320 | } | |
321 | if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) { | |
65ff5b7d ST |
322 | if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_METADATA, |
323 | hash_block)) { | |
324 | r = -EIO; | |
325 | goto release_ret_r; | |
326 | } | |
a4ffc152 MP |
327 | } else |
328 | aux->hash_verified = 1; | |
329 | } | |
330 | ||
331 | data += offset; | |
332 | ||
333 | memcpy(io_want_digest(v, io), data, v->digest_size); | |
334 | ||
335 | dm_bufio_release(buf); | |
336 | return 0; | |
337 | ||
338 | release_ret_r: | |
339 | dm_bufio_release(buf); | |
340 | ||
341 | return r; | |
342 | } | |
343 | ||
344 | /* | |
345 | * Verify one "dm_verity_io" structure. | |
346 | */ | |
347 | static int verity_verify_io(struct dm_verity_io *io) | |
348 | { | |
349 | struct dm_verity *v = io->v; | |
003b5c57 KO |
350 | struct bio *bio = dm_bio_from_per_bio_data(io, |
351 | v->ti->per_bio_data_size); | |
a4ffc152 MP |
352 | unsigned b; |
353 | int i; | |
a4ffc152 MP |
354 | |
355 | for (b = 0; b < io->n_blocks; b++) { | |
356 | struct shash_desc *desc; | |
357 | u8 *result; | |
358 | int r; | |
359 | unsigned todo; | |
360 | ||
361 | if (likely(v->levels)) { | |
362 | /* | |
363 | * First, we try to get the requested hash for | |
364 | * the current block. If the hash block itself is | |
365 | * verified, zero is returned. If it isn't, this | |
366 | * function returns 0 and we fall back to whole | |
367 | * chain verification. | |
368 | */ | |
369 | int r = verity_verify_level(io, io->block + b, 0, true); | |
370 | if (likely(!r)) | |
371 | goto test_block_hash; | |
372 | if (r < 0) | |
373 | return r; | |
374 | } | |
375 | ||
376 | memcpy(io_want_digest(v, io), v->root_digest, v->digest_size); | |
377 | ||
378 | for (i = v->levels - 1; i >= 0; i--) { | |
379 | int r = verity_verify_level(io, io->block + b, i, false); | |
380 | if (unlikely(r)) | |
381 | return r; | |
382 | } | |
383 | ||
384 | test_block_hash: | |
385 | desc = io_hash_desc(v, io); | |
386 | desc->tfm = v->tfm; | |
387 | desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP; | |
388 | r = crypto_shash_init(desc); | |
389 | if (r < 0) { | |
390 | DMERR("crypto_shash_init failed: %d", r); | |
391 | return r; | |
392 | } | |
393 | ||
394 | if (likely(v->version >= 1)) { | |
395 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
396 | if (r < 0) { | |
397 | DMERR("crypto_shash_update failed: %d", r); | |
398 | return r; | |
399 | } | |
400 | } | |
a4ffc152 | 401 | todo = 1 << v->data_dev_block_bits; |
3a774521 | 402 | do { |
a4ffc152 | 403 | u8 *page; |
3a774521 | 404 | unsigned len; |
003b5c57 KO |
405 | struct bio_vec bv = bio_iter_iovec(bio, io->iter); |
406 | ||
407 | page = kmap_atomic(bv.bv_page); | |
3a774521 MB |
408 | len = bv.bv_len; |
409 | if (likely(len >= todo)) | |
410 | len = todo; | |
411 | r = crypto_shash_update(desc, page + bv.bv_offset, len); | |
a4ffc152 | 412 | kunmap_atomic(page); |
003b5c57 | 413 | |
a4ffc152 MP |
414 | if (r < 0) { |
415 | DMERR("crypto_shash_update failed: %d", r); | |
416 | return r; | |
417 | } | |
003b5c57 | 418 | |
3a774521 MB |
419 | bio_advance_iter(bio, &io->iter, len); |
420 | todo -= len; | |
421 | } while (todo); | |
a4ffc152 MP |
422 | |
423 | if (!v->version) { | |
424 | r = crypto_shash_update(desc, v->salt, v->salt_size); | |
425 | if (r < 0) { | |
426 | DMERR("crypto_shash_update failed: %d", r); | |
427 | return r; | |
428 | } | |
429 | } | |
430 | ||
431 | result = io_real_digest(v, io); | |
432 | r = crypto_shash_final(desc, result); | |
433 | if (r < 0) { | |
434 | DMERR("crypto_shash_final failed: %d", r); | |
435 | return r; | |
436 | } | |
437 | if (unlikely(memcmp(result, io_want_digest(v, io), v->digest_size))) { | |
65ff5b7d ST |
438 | if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA, |
439 | io->block + b)) | |
440 | return -EIO; | |
a4ffc152 MP |
441 | } |
442 | } | |
a4ffc152 MP |
443 | |
444 | return 0; | |
445 | } | |
446 | ||
447 | /* | |
448 | * End one "io" structure with a given error. | |
449 | */ | |
450 | static void verity_finish_io(struct dm_verity_io *io, int error) | |
451 | { | |
a4ffc152 | 452 | struct dm_verity *v = io->v; |
e42c3f91 | 453 | struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_bio_data_size); |
a4ffc152 MP |
454 | |
455 | bio->bi_end_io = io->orig_bi_end_io; | |
456 | bio->bi_private = io->orig_bi_private; | |
4246a0b6 | 457 | bio->bi_error = error; |
a4ffc152 | 458 | |
4246a0b6 | 459 | bio_endio(bio); |
a4ffc152 MP |
460 | } |
461 | ||
462 | static void verity_work(struct work_struct *w) | |
463 | { | |
464 | struct dm_verity_io *io = container_of(w, struct dm_verity_io, work); | |
465 | ||
466 | verity_finish_io(io, verity_verify_io(io)); | |
467 | } | |
468 | ||
4246a0b6 | 469 | static void verity_end_io(struct bio *bio) |
a4ffc152 MP |
470 | { |
471 | struct dm_verity_io *io = bio->bi_private; | |
472 | ||
4246a0b6 CH |
473 | if (bio->bi_error) { |
474 | verity_finish_io(io, bio->bi_error); | |
a4ffc152 MP |
475 | return; |
476 | } | |
477 | ||
478 | INIT_WORK(&io->work, verity_work); | |
479 | queue_work(io->v->verify_wq, &io->work); | |
480 | } | |
481 | ||
482 | /* | |
483 | * Prefetch buffers for the specified io. | |
484 | * The root buffer is not prefetched, it is assumed that it will be cached | |
485 | * all the time. | |
486 | */ | |
3b6b7813 | 487 | static void verity_prefetch_io(struct work_struct *work) |
a4ffc152 | 488 | { |
3b6b7813 MP |
489 | struct dm_verity_prefetch_work *pw = |
490 | container_of(work, struct dm_verity_prefetch_work, work); | |
491 | struct dm_verity *v = pw->v; | |
a4ffc152 MP |
492 | int i; |
493 | ||
494 | for (i = v->levels - 2; i >= 0; i--) { | |
495 | sector_t hash_block_start; | |
496 | sector_t hash_block_end; | |
3b6b7813 MP |
497 | verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL); |
498 | verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL); | |
a4ffc152 | 499 | if (!i) { |
fe5fe906 | 500 | unsigned cluster = ACCESS_ONCE(dm_verity_prefetch_cluster); |
a4ffc152 MP |
501 | |
502 | cluster >>= v->data_dev_block_bits; | |
503 | if (unlikely(!cluster)) | |
504 | goto no_prefetch_cluster; | |
505 | ||
506 | if (unlikely(cluster & (cluster - 1))) | |
553d8fe0 | 507 | cluster = 1 << __fls(cluster); |
a4ffc152 MP |
508 | |
509 | hash_block_start &= ~(sector_t)(cluster - 1); | |
510 | hash_block_end |= cluster - 1; | |
511 | if (unlikely(hash_block_end >= v->hash_blocks)) | |
512 | hash_block_end = v->hash_blocks - 1; | |
513 | } | |
514 | no_prefetch_cluster: | |
515 | dm_bufio_prefetch(v->bufio, hash_block_start, | |
516 | hash_block_end - hash_block_start + 1); | |
517 | } | |
3b6b7813 MP |
518 | |
519 | kfree(pw); | |
520 | } | |
521 | ||
522 | static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io) | |
523 | { | |
524 | struct dm_verity_prefetch_work *pw; | |
525 | ||
526 | pw = kmalloc(sizeof(struct dm_verity_prefetch_work), | |
527 | GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
528 | ||
529 | if (!pw) | |
530 | return; | |
531 | ||
532 | INIT_WORK(&pw->work, verity_prefetch_io); | |
533 | pw->v = v; | |
534 | pw->block = io->block; | |
535 | pw->n_blocks = io->n_blocks; | |
536 | queue_work(v->verify_wq, &pw->work); | |
a4ffc152 MP |
537 | } |
538 | ||
539 | /* | |
540 | * Bio map function. It allocates dm_verity_io structure and bio vector and | |
541 | * fills them. Then it issues prefetches and the I/O. | |
542 | */ | |
7de3ee57 | 543 | static int verity_map(struct dm_target *ti, struct bio *bio) |
a4ffc152 MP |
544 | { |
545 | struct dm_verity *v = ti->private; | |
546 | struct dm_verity_io *io; | |
547 | ||
548 | bio->bi_bdev = v->data_dev->bdev; | |
4f024f37 | 549 | bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector); |
a4ffc152 | 550 | |
4f024f37 | 551 | if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) & |
a4ffc152 MP |
552 | ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) { |
553 | DMERR_LIMIT("unaligned io"); | |
554 | return -EIO; | |
555 | } | |
556 | ||
f73a1c7d | 557 | if (bio_end_sector(bio) >> |
a4ffc152 MP |
558 | (v->data_dev_block_bits - SECTOR_SHIFT) > v->data_blocks) { |
559 | DMERR_LIMIT("io out of range"); | |
560 | return -EIO; | |
561 | } | |
562 | ||
563 | if (bio_data_dir(bio) == WRITE) | |
564 | return -EIO; | |
565 | ||
e42c3f91 | 566 | io = dm_per_bio_data(bio, ti->per_bio_data_size); |
a4ffc152 | 567 | io->v = v; |
a4ffc152 MP |
568 | io->orig_bi_end_io = bio->bi_end_io; |
569 | io->orig_bi_private = bio->bi_private; | |
4f024f37 KO |
570 | io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT); |
571 | io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits; | |
a4ffc152 MP |
572 | |
573 | bio->bi_end_io = verity_end_io; | |
574 | bio->bi_private = io; | |
003b5c57 | 575 | io->iter = bio->bi_iter; |
a4ffc152 | 576 | |
3b6b7813 | 577 | verity_submit_prefetch(v, io); |
a4ffc152 MP |
578 | |
579 | generic_make_request(bio); | |
580 | ||
581 | return DM_MAPIO_SUBMITTED; | |
582 | } | |
583 | ||
584 | /* | |
585 | * Status: V (valid) or C (corruption found) | |
586 | */ | |
fd7c092e MP |
587 | static void verity_status(struct dm_target *ti, status_type_t type, |
588 | unsigned status_flags, char *result, unsigned maxlen) | |
a4ffc152 MP |
589 | { |
590 | struct dm_verity *v = ti->private; | |
591 | unsigned sz = 0; | |
592 | unsigned x; | |
593 | ||
594 | switch (type) { | |
595 | case STATUSTYPE_INFO: | |
596 | DMEMIT("%c", v->hash_failed ? 'C' : 'V'); | |
597 | break; | |
598 | case STATUSTYPE_TABLE: | |
599 | DMEMIT("%u %s %s %u %u %llu %llu %s ", | |
600 | v->version, | |
601 | v->data_dev->name, | |
602 | v->hash_dev->name, | |
603 | 1 << v->data_dev_block_bits, | |
604 | 1 << v->hash_dev_block_bits, | |
605 | (unsigned long long)v->data_blocks, | |
606 | (unsigned long long)v->hash_start, | |
607 | v->alg_name | |
608 | ); | |
609 | for (x = 0; x < v->digest_size; x++) | |
610 | DMEMIT("%02x", v->root_digest[x]); | |
611 | DMEMIT(" "); | |
612 | if (!v->salt_size) | |
613 | DMEMIT("-"); | |
614 | else | |
615 | for (x = 0; x < v->salt_size; x++) | |
616 | DMEMIT("%02x", v->salt[x]); | |
65ff5b7d ST |
617 | if (v->mode != DM_VERITY_MODE_EIO) { |
618 | DMEMIT(" 1 "); | |
619 | switch (v->mode) { | |
620 | case DM_VERITY_MODE_LOGGING: | |
621 | DMEMIT(DM_VERITY_OPT_LOGGING); | |
622 | break; | |
623 | case DM_VERITY_MODE_RESTART: | |
624 | DMEMIT(DM_VERITY_OPT_RESTART); | |
625 | break; | |
626 | default: | |
627 | BUG(); | |
628 | } | |
629 | } | |
a4ffc152 MP |
630 | break; |
631 | } | |
a4ffc152 MP |
632 | } |
633 | ||
e56f81e0 CH |
634 | static int verity_prepare_ioctl(struct dm_target *ti, |
635 | struct block_device **bdev, fmode_t *mode) | |
a4ffc152 MP |
636 | { |
637 | struct dm_verity *v = ti->private; | |
e56f81e0 CH |
638 | |
639 | *bdev = v->data_dev->bdev; | |
a4ffc152 MP |
640 | |
641 | if (v->data_start || | |
642 | ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT) | |
e56f81e0 CH |
643 | return 1; |
644 | return 0; | |
a4ffc152 MP |
645 | } |
646 | ||
a4ffc152 MP |
647 | static int verity_iterate_devices(struct dm_target *ti, |
648 | iterate_devices_callout_fn fn, void *data) | |
649 | { | |
650 | struct dm_verity *v = ti->private; | |
651 | ||
652 | return fn(ti, v->data_dev, v->data_start, ti->len, data); | |
653 | } | |
654 | ||
655 | static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits) | |
656 | { | |
657 | struct dm_verity *v = ti->private; | |
658 | ||
659 | if (limits->logical_block_size < 1 << v->data_dev_block_bits) | |
660 | limits->logical_block_size = 1 << v->data_dev_block_bits; | |
661 | ||
662 | if (limits->physical_block_size < 1 << v->data_dev_block_bits) | |
663 | limits->physical_block_size = 1 << v->data_dev_block_bits; | |
664 | ||
665 | blk_limits_io_min(limits, limits->logical_block_size); | |
666 | } | |
667 | ||
668 | static void verity_dtr(struct dm_target *ti) | |
669 | { | |
670 | struct dm_verity *v = ti->private; | |
671 | ||
672 | if (v->verify_wq) | |
673 | destroy_workqueue(v->verify_wq); | |
674 | ||
a4ffc152 MP |
675 | if (v->bufio) |
676 | dm_bufio_client_destroy(v->bufio); | |
677 | ||
678 | kfree(v->salt); | |
679 | kfree(v->root_digest); | |
680 | ||
681 | if (v->tfm) | |
682 | crypto_free_shash(v->tfm); | |
683 | ||
684 | kfree(v->alg_name); | |
685 | ||
686 | if (v->hash_dev) | |
687 | dm_put_device(ti, v->hash_dev); | |
688 | ||
689 | if (v->data_dev) | |
690 | dm_put_device(ti, v->data_dev); | |
691 | ||
692 | kfree(v); | |
693 | } | |
694 | ||
695 | /* | |
696 | * Target parameters: | |
697 | * <version> The current format is version 1. | |
698 | * Vsn 0 is compatible with original Chromium OS releases. | |
699 | * <data device> | |
700 | * <hash device> | |
701 | * <data block size> | |
702 | * <hash block size> | |
703 | * <the number of data blocks> | |
704 | * <hash start block> | |
705 | * <algorithm> | |
706 | * <digest> | |
707 | * <salt> Hex string or "-" if no salt. | |
708 | */ | |
709 | static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) | |
710 | { | |
711 | struct dm_verity *v; | |
65ff5b7d ST |
712 | struct dm_arg_set as; |
713 | const char *opt_string; | |
714 | unsigned int num, opt_params; | |
a4ffc152 MP |
715 | unsigned long long num_ll; |
716 | int r; | |
717 | int i; | |
718 | sector_t hash_position; | |
719 | char dummy; | |
720 | ||
65ff5b7d ST |
721 | static struct dm_arg _args[] = { |
722 | {0, 1, "Invalid number of feature args"}, | |
723 | }; | |
724 | ||
a4ffc152 MP |
725 | v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL); |
726 | if (!v) { | |
727 | ti->error = "Cannot allocate verity structure"; | |
728 | return -ENOMEM; | |
729 | } | |
730 | ti->private = v; | |
731 | v->ti = ti; | |
732 | ||
733 | if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) { | |
734 | ti->error = "Device must be readonly"; | |
735 | r = -EINVAL; | |
736 | goto bad; | |
737 | } | |
738 | ||
65ff5b7d ST |
739 | if (argc < 10) { |
740 | ti->error = "Not enough arguments"; | |
a4ffc152 MP |
741 | r = -EINVAL; |
742 | goto bad; | |
743 | } | |
744 | ||
5d8be843 MP |
745 | if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 || |
746 | num > 1) { | |
a4ffc152 MP |
747 | ti->error = "Invalid version"; |
748 | r = -EINVAL; | |
749 | goto bad; | |
750 | } | |
751 | v->version = num; | |
752 | ||
753 | r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev); | |
754 | if (r) { | |
755 | ti->error = "Data device lookup failed"; | |
756 | goto bad; | |
757 | } | |
758 | ||
759 | r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev); | |
760 | if (r) { | |
761 | ti->error = "Data device lookup failed"; | |
762 | goto bad; | |
763 | } | |
764 | ||
765 | if (sscanf(argv[3], "%u%c", &num, &dummy) != 1 || | |
766 | !num || (num & (num - 1)) || | |
767 | num < bdev_logical_block_size(v->data_dev->bdev) || | |
768 | num > PAGE_SIZE) { | |
769 | ti->error = "Invalid data device block size"; | |
770 | r = -EINVAL; | |
771 | goto bad; | |
772 | } | |
553d8fe0 | 773 | v->data_dev_block_bits = __ffs(num); |
a4ffc152 MP |
774 | |
775 | if (sscanf(argv[4], "%u%c", &num, &dummy) != 1 || | |
776 | !num || (num & (num - 1)) || | |
777 | num < bdev_logical_block_size(v->hash_dev->bdev) || | |
778 | num > INT_MAX) { | |
779 | ti->error = "Invalid hash device block size"; | |
780 | r = -EINVAL; | |
781 | goto bad; | |
782 | } | |
553d8fe0 | 783 | v->hash_dev_block_bits = __ffs(num); |
a4ffc152 MP |
784 | |
785 | if (sscanf(argv[5], "%llu%c", &num_ll, &dummy) != 1 || | |
1d55f6bc MP |
786 | (sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) |
787 | >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll) { | |
a4ffc152 MP |
788 | ti->error = "Invalid data blocks"; |
789 | r = -EINVAL; | |
790 | goto bad; | |
791 | } | |
792 | v->data_blocks = num_ll; | |
793 | ||
794 | if (ti->len > (v->data_blocks << (v->data_dev_block_bits - SECTOR_SHIFT))) { | |
795 | ti->error = "Data device is too small"; | |
796 | r = -EINVAL; | |
797 | goto bad; | |
798 | } | |
799 | ||
800 | if (sscanf(argv[6], "%llu%c", &num_ll, &dummy) != 1 || | |
1d55f6bc MP |
801 | (sector_t)(num_ll << (v->hash_dev_block_bits - SECTOR_SHIFT)) |
802 | >> (v->hash_dev_block_bits - SECTOR_SHIFT) != num_ll) { | |
a4ffc152 MP |
803 | ti->error = "Invalid hash start"; |
804 | r = -EINVAL; | |
805 | goto bad; | |
806 | } | |
807 | v->hash_start = num_ll; | |
808 | ||
809 | v->alg_name = kstrdup(argv[7], GFP_KERNEL); | |
810 | if (!v->alg_name) { | |
811 | ti->error = "Cannot allocate algorithm name"; | |
812 | r = -ENOMEM; | |
813 | goto bad; | |
814 | } | |
815 | ||
816 | v->tfm = crypto_alloc_shash(v->alg_name, 0, 0); | |
817 | if (IS_ERR(v->tfm)) { | |
818 | ti->error = "Cannot initialize hash function"; | |
819 | r = PTR_ERR(v->tfm); | |
820 | v->tfm = NULL; | |
821 | goto bad; | |
822 | } | |
823 | v->digest_size = crypto_shash_digestsize(v->tfm); | |
824 | if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) { | |
825 | ti->error = "Digest size too big"; | |
826 | r = -EINVAL; | |
827 | goto bad; | |
828 | } | |
829 | v->shash_descsize = | |
830 | sizeof(struct shash_desc) + crypto_shash_descsize(v->tfm); | |
831 | ||
832 | v->root_digest = kmalloc(v->digest_size, GFP_KERNEL); | |
833 | if (!v->root_digest) { | |
834 | ti->error = "Cannot allocate root digest"; | |
835 | r = -ENOMEM; | |
836 | goto bad; | |
837 | } | |
838 | if (strlen(argv[8]) != v->digest_size * 2 || | |
839 | hex2bin(v->root_digest, argv[8], v->digest_size)) { | |
840 | ti->error = "Invalid root digest"; | |
841 | r = -EINVAL; | |
842 | goto bad; | |
843 | } | |
844 | ||
845 | if (strcmp(argv[9], "-")) { | |
846 | v->salt_size = strlen(argv[9]) / 2; | |
847 | v->salt = kmalloc(v->salt_size, GFP_KERNEL); | |
848 | if (!v->salt) { | |
849 | ti->error = "Cannot allocate salt"; | |
850 | r = -ENOMEM; | |
851 | goto bad; | |
852 | } | |
853 | if (strlen(argv[9]) != v->salt_size * 2 || | |
854 | hex2bin(v->salt, argv[9], v->salt_size)) { | |
855 | ti->error = "Invalid salt"; | |
856 | r = -EINVAL; | |
857 | goto bad; | |
858 | } | |
859 | } | |
860 | ||
65ff5b7d ST |
861 | argv += 10; |
862 | argc -= 10; | |
863 | ||
864 | /* Optional parameters */ | |
865 | if (argc) { | |
866 | as.argc = argc; | |
867 | as.argv = argv; | |
868 | ||
869 | r = dm_read_arg_group(_args, &as, &opt_params, &ti->error); | |
870 | if (r) | |
871 | goto bad; | |
872 | ||
873 | while (opt_params) { | |
874 | opt_params--; | |
875 | opt_string = dm_shift_arg(&as); | |
876 | if (!opt_string) { | |
877 | ti->error = "Not enough feature arguments"; | |
878 | r = -EINVAL; | |
879 | goto bad; | |
880 | } | |
881 | ||
882 | if (!strcasecmp(opt_string, DM_VERITY_OPT_LOGGING)) | |
883 | v->mode = DM_VERITY_MODE_LOGGING; | |
884 | else if (!strcasecmp(opt_string, DM_VERITY_OPT_RESTART)) | |
885 | v->mode = DM_VERITY_MODE_RESTART; | |
886 | else { | |
887 | ti->error = "Invalid feature arguments"; | |
888 | r = -EINVAL; | |
889 | goto bad; | |
890 | } | |
891 | } | |
892 | } | |
893 | ||
a4ffc152 | 894 | v->hash_per_block_bits = |
553d8fe0 | 895 | __fls((1 << v->hash_dev_block_bits) / v->digest_size); |
a4ffc152 MP |
896 | |
897 | v->levels = 0; | |
898 | if (v->data_blocks) | |
899 | while (v->hash_per_block_bits * v->levels < 64 && | |
900 | (unsigned long long)(v->data_blocks - 1) >> | |
901 | (v->hash_per_block_bits * v->levels)) | |
902 | v->levels++; | |
903 | ||
904 | if (v->levels > DM_VERITY_MAX_LEVELS) { | |
905 | ti->error = "Too many tree levels"; | |
906 | r = -E2BIG; | |
907 | goto bad; | |
908 | } | |
909 | ||
910 | hash_position = v->hash_start; | |
911 | for (i = v->levels - 1; i >= 0; i--) { | |
912 | sector_t s; | |
913 | v->hash_level_block[i] = hash_position; | |
b1bf2de0 MP |
914 | s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1) |
915 | >> ((i + 1) * v->hash_per_block_bits); | |
a4ffc152 MP |
916 | if (hash_position + s < hash_position) { |
917 | ti->error = "Hash device offset overflow"; | |
918 | r = -E2BIG; | |
919 | goto bad; | |
920 | } | |
921 | hash_position += s; | |
922 | } | |
923 | v->hash_blocks = hash_position; | |
924 | ||
925 | v->bufio = dm_bufio_client_create(v->hash_dev->bdev, | |
926 | 1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux), | |
927 | dm_bufio_alloc_callback, NULL); | |
928 | if (IS_ERR(v->bufio)) { | |
929 | ti->error = "Cannot initialize dm-bufio"; | |
930 | r = PTR_ERR(v->bufio); | |
931 | v->bufio = NULL; | |
932 | goto bad; | |
933 | } | |
934 | ||
935 | if (dm_bufio_get_device_size(v->bufio) < v->hash_blocks) { | |
936 | ti->error = "Hash device is too small"; | |
937 | r = -E2BIG; | |
938 | goto bad; | |
939 | } | |
940 | ||
e42c3f91 | 941 | ti->per_bio_data_size = roundup(sizeof(struct dm_verity_io) + v->shash_descsize + v->digest_size * 2, __alignof__(struct dm_verity_io)); |
a4ffc152 | 942 | |
a4ffc152 MP |
943 | /* WQ_UNBOUND greatly improves performance when running on ramdisk */ |
944 | v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus()); | |
945 | if (!v->verify_wq) { | |
946 | ti->error = "Cannot allocate workqueue"; | |
947 | r = -ENOMEM; | |
948 | goto bad; | |
949 | } | |
950 | ||
951 | return 0; | |
952 | ||
953 | bad: | |
954 | verity_dtr(ti); | |
955 | ||
956 | return r; | |
957 | } | |
958 | ||
959 | static struct target_type verity_target = { | |
960 | .name = "verity", | |
3b6b7813 | 961 | .version = {1, 2, 0}, |
a4ffc152 MP |
962 | .module = THIS_MODULE, |
963 | .ctr = verity_ctr, | |
964 | .dtr = verity_dtr, | |
965 | .map = verity_map, | |
966 | .status = verity_status, | |
e56f81e0 | 967 | .prepare_ioctl = verity_prepare_ioctl, |
a4ffc152 MP |
968 | .iterate_devices = verity_iterate_devices, |
969 | .io_hints = verity_io_hints, | |
970 | }; | |
971 | ||
972 | static int __init dm_verity_init(void) | |
973 | { | |
974 | int r; | |
975 | ||
976 | r = dm_register_target(&verity_target); | |
977 | if (r < 0) | |
978 | DMERR("register failed %d", r); | |
979 | ||
980 | return r; | |
981 | } | |
982 | ||
983 | static void __exit dm_verity_exit(void) | |
984 | { | |
985 | dm_unregister_target(&verity_target); | |
986 | } | |
987 | ||
988 | module_init(dm_verity_init); | |
989 | module_exit(dm_verity_exit); | |
990 | ||
991 | MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>"); | |
992 | MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>"); | |
993 | MODULE_AUTHOR("Will Drewry <wad@chromium.org>"); | |
994 | MODULE_DESCRIPTION(DM_NAME " target for transparent disk integrity checking"); | |
995 | MODULE_LICENSE("GPL"); |